Finer-grained locks

[cellio]

The abilities work added locks to the Tools menu. This is good, but it's a little coarser-grained than we intended. Now that the framework is in place, let's adjust these.

Currently you can lock a post entirely (edits, votes, comments), or you can disable comments:

Our initial goal (as described in these use cases) was to have two types of locks, edit lock and comment lock. I see no reason to lock a post from voting, and the way to prevent new answers to a question is to close it. We've left open the possibility of other lock types, but we haven't identified any others.

Can we change the "lock" entry here to an edit lock, which, with the next one, together satisfies most of this goal? Both are gated by the Curate ability, with permanent locks being a Moderator ability. (The use cases also specify that a Curator lock should raise an auto-flag for moderators so they know to look at it; if that's hard to do here we can defer it.)